Features of actomyosin superprecipitation reaction in different environment conditions

The influence of divalent cations (Cd2+, Zn2+, Sr2+) and staphylococcus protein A on the superprecipitation reaction of cardiac muscle actomyosin was investigated using methods of preparative protein chemistry, optical spectroscopy and mechanokinetic analysis. It was shown that the metal ions in the range of concentrations 0.1–5 mM inhibit the Mg2+-dependent SPP reaction of actomyosin cardiac muscle and alter the kinetic parameters of this process. It was revealed that protein A modulates superprecipitation dynamics decreasing the maximal value of optical density and time of its halfmaximum achievement as well as starting and normalized superprecipitation rates. Thus, investigated factors are able to influence the actin myosin interaction changing their functional parameters of proteins from cardiomyocyte contractile complex. The kinetic characteristics of actomyosin superprecipitation are sensitive to the influence of physicochemical and pharmacological factors and can be used to study their influence on the molecular mechanisms of muscle contraction.